<script src="../Meta.js"></script>
<script>
var hi = 'global';

// one.
function W() {
}
W.prototype = window;

w = new W();
alert(w == window);  // false
alert(window == w);  // true

// two.
var t = window;
function W() {
}
W.prototype = Unique(window)
w = new W();
w.hi = 'hi, obj';
w.window = w;
alert(t === w.window);  // show 'true', write invaild.
</script>